154 A RESEARCH ON THE EUCALYPTS OF TASMANIA 



saponification number for the esters and free acid was 14'8. 

 The specific gravity of the crude oil at 15*^ C. = 0'9138, 

 and of the rectified oil = 091 17. The rotation a^ = 

 + 8'5^; and refractive index at 16° = 1'4695. The recti- 

 fied oil may be considered of excellent quality for phar- 

 maceutical purposes, judged by the present standard for 

 these oils. 



EUCALYPTUS GLOBULUS, Labill. 



(''Blue Gum:') 



Botany. 



Historicnl. — This species was described by Labillardier 

 from trees growing in Tasmania, and recorded in "his 

 " Voyage " (I. 153. f. 13.), published in 1799. 



Bemarl-s. — Tasmania may be regarded as the home of 

 E . glohulus, and to-day it has such a world-wide reputa- 

 tion, and is so familiar to botanists, foresters, and the 

 commercial world generally, that nothing is required here 

 to mark its identification. It is known the world over. 



Its botanical and chemical characters never seem to alter 

 whatever hemisphere it may be planted in. 



E . glohulus has been recorded as far north in New South 

 Wales as Rylstone (R. T. B., Proc. Linn. Soc. N.S.W., 

 1896). 



Chemistry. 



Essentud Oil. — The oil of this species is so well known 

 that it is quite unnecessary to describe it here. It is now 

 generally recognised that wherever this species grows the 

 general characters of the oil are the same. We have deter- 

 mined this to be also the case with trees of E. globulus 

 growing in New South Wales, and no matter whether these 

 were growing naturally or under cultivation the oil was 

 always in agreement with that obtained from Tasmanian 

 trees. There is nothing unusual, however, about this, nor 

 is it peculiar to this species. From hundreds of analyses 

 we have now made from various species, and from 

 authentic botanical material, it is found that the chemical 

 characteristics of a Eucalyptus species are some of the 

 most constant features of the plant, and the determination 

 of these has now become of considerable aid in the botanical 

 characterisation between doubtful species and supposed 

 allied forms. 



